Sushi date night help :)

This is probably too late to help, but avoid the fried stuff (tempuras) and volcano rolls always seem to be higher in calories. If they have stuff with brown rice and/or quinoa, you'll get more nutrients that way (over plain white rice). My sushi go-tos are usually raw tuna rolls or cooked shrimp rolls. Both typically run about 250 calories. From my limited observations, one or two sushi rolls would likely fit into a 600 meal!

Sashimi for next time.

I order a sunshine roll or other rolls with a small amount of ingredients so I can keep it simple. I don't use any sauces as good rolls are delicious on their own. I only have sushi every couple of months so I do my best to estimate calories. If I am off, it is only one meal.

In the future you can sometimes ask them to replace the rice with cucumber in the roll, or to go very light on the rice, or no rice. That will save you quite a few calories. But I agree with the above poster - I typically avoid all tempura, anything with the masago or mayo, or cream cheese at that adds up quickly.
Also, a seaweed salad is filling and delicious!